Within food industry in general and dairy industry in particular use is made of spray dryers. In such a spray dryer liquid food product is forced through a spray nozzle or atomized in another way, mixed with hot air (or entrained into a fast flow of hot air) of and injected into a drying chamber. Any residual water is evaporated and the resulting powder is collected at the bottom of the drying chamber. The result may be a dried powder, e.g. milk powder. Though only described in a few words, the performance of the nozzle is critical for the performance of the overall process of drying the product. The performance and characteristics of the spray nozzle may also have an impact on the particle size. While feeds, temperatures and pressures etc. are parameters that are readily controlled and monitored by standard sensor arrangements, e.g. mass flow meters, thermocouples, pressure sensors, the performance of the spray is not as readily controlled and monitored. The atmosphere inside the drying chamber is harsh, with high temperature, high-speed flows and potentially abrasive particles.
One such system is disclosed in US2012287285 and the present disclosure suggests a improved system for control of the spray forming process.